intrinsic-factor and fura-2-am

The aim of this study was to elucidate the cellular mechanisms of action of epidermal growth factor (EGF) inhibition of parietal cell secretion. EGF effects on histamine- and carbachol-stimulated [14C]aminopyrine (AP) uptake and intrinsic factor (IF) secretion were evaluated in isolated rabbit parietal cells. EGF inhibited histamine-stimulated [14C]AP uptake and IF secretion through a reduction in stimulated adenosine 3',5'-cyclic monophosphate (cAMP) levels. EGF decreased the phosphorylation of a cytosolic 30-kDa, histamine-stimulated, cAMP-dependent protein kinase substrate. These effects on histamine-stimulated activation were reversed by pertussis toxin preincubation. EGF inhibited carbachol-stimulated [14C]AP uptake and IF secretion, but did not alter the carbachol-stimulated Ca2+ transient. These results indicate that EGF inhibits histamine-stimulated secretion through the inhibitory Gi guanosine 5'-triphosphate-binding protein and carbachol-stimulated secretion through a mechanism independent of the activation of an increase in intracellular Ca2+.

Topics: Aminopyrine; Animals; Benzofurans; Buffers; Calcium; Carbachol; Colforsin; Cyclic AMP; Cytosol; Epidermal Growth Factor; Fluorescent Dyes; Fura-2; Gastric Acid; Histamine; In Vitro Techniques; Intrinsic Factor; Kinetics; Parietal Cells, Gastric; Phosphorylation; Proteins; Rabbits; Signal Transduction